Press for forming plastic articles



Dec. 13, 1927. 1,652,991

a aWv/M 123% Awys.

Dec 13, 1927 1,652,991

L. w. HOTTEL- PRESS FOR FORMING PLASTIC ARTICLES Filed Nome. 1925 4 smu m 5 a 50 l @a a 75 3' x 7 a i T iii -9 y W W 4 Sheets-Sheet 4 Filed Nov. 2, 1925 L W HOTTEL PRESS FOR FORMING PLASTIC ARTICLES Patented Dec. 13, 1927.

UNITED STATES PATENT OFFICE.

LOUIS W. HOTTEL, OF ERIE, PENNSYLVANIA.

Panes For. ronmme PLASTIC narrows.

.Application filed November 2, 1925. Serial No. 66,312.

facturing battery containers of similar articles of hard rubber and vulcanizing the same.

Prior to my invention such articles have usually been 'made by uniting calendered sheets of rubber into the form and shape of a battery container, assembling a mold around such articlev and closing the mold under pressure and heat wherebythe article was molded and vulcanized. After vulcanization it was necessary to remove the cores which formed the interior and this required considerable force and took considerable time as the cores were held in place by adhesion and atmospheric pressure. The removing of the cores was, as far as I am aware, accomplished in a second operation.

One of the objects of my invention is to produce a press or machine in which the various parts of the mold may be held in relation to each other for. assembling and disassembling whereby such parts may be opened and closed automatically avoiding a large amount of hand labor.

Another object is to produce a press in which the stripping of the cores is automatically accomplished subsequent to' the molding operation without transfer of the articl to other devices.

A further object is to. form the article in inverted position whereby automatic draina e fromithe steam heated cores is accomp shed.

Other objects and advantages of my invention will appear from the following description and the accompanying drawings.

Fig. 1 is a front elevation of a preferred form of my invention. I

Fig. 2 is a side elevation, partly insection, of the same.

Fig. 3 is a sectional elevation of the mold parts and part of the associated mechanism.

Fig. 4 shows detail views of a slightly modified form;

Fig. 5 is an edge view showing the interlocking portions of the end plates.

. Fig. 6 shows detail views of a modified.

form of end plates.

Fig. 7 is a vertical section through one of the core members and bottom plate.

Fig. 8 is a section through the core member at right angles to- Fi 7.

Fig. 9 IS a plan viewof the bottom plate.

Fig. 10 is a side elevation of same partly in section.

Fig. 11 is a. detail sectional view showing a modified form of connection between front mold plate and top mold plate.

Referring to the drawings:

' The press or machine consists essentially of an assembly of mold parts corresponding to the article to be manufactured and mechanism for closing and opening the mold.

The mechanism for closing the mold and applying pressure thereto may be of various forms but in the preferred form illustrated consists of a hydraulic press consisting of a cylinder 1 which constitutes the base of the machine, a press head 2 spaced from the cylinder by rods 3, a ram 4 mounted in the cylinder 1 and carrying a lower platen 5 opposed to the press head. This mechanism is old in the artand needs no further description. Below the head 2 of the press, I rigidly mount a mold chamber 6 provided with one or more .mold cavities 6 extending through the chamber and having tapered walls so that the openings on the lower side are larger than those on the upper side. In the form shown, two such cavities are present. The mold chamber is also provided with suitable connecting tunnels 6 whereby the mold chamber may be heated by steam from a convenient source.

- The mold boxes or liners consist each of a top plate 7, two'end lates 8, and two side plates 9, so fitted toget er that they form a separable box open on the lower side only and of tapered formation outside so that the mold fits exactly in one of themold cavities 6 of the mold chamber. The plates 7, 8 and 9 ing the article in the desired configuration and may be changed at will and others substituted therefor. To this end the top late 7 is and the end plates 8 and side plates 9 areeach provided with corresponding convex are provided with surfaces suitable for moldshoulders 8 and 9 whereby said end and side plates are loosely suspended from theupper edges of all the mold plates may be the same. However, where it is desired to use presses with less motion and consequent saving in hydraulic power and time of opening and closing one or more of the plates, such as front plate 9 may be modified in construction so as to be removable and replaceable by hand. To accomplish this the edgeof such a plate may be made like that shown in Fig. 4. In this construction the convex portion of the edge has been removed and a portion of the back of the plate adjacent thereto has been cut away as at 9 to provide clearance so that by grasping the front plate and pulling it forward laterally it may be'unfastened from the assembly.

All of the mold plates are preferably provided with raised panels 8 and 9 which impart a paneled appearance to the molded article and also act as dowels to prevent premature relative motion between the mold and molded article.

\Vhere an article such as a battery container is-to be provided with integral handles at the ends, the plates 8 are made of -such configuration as to provide extensions of the main cavity for this purpose as shown in Fig. 6.

For forn'iingthe interior of the article, I provide one or more cores corresponding in number to the mold boxes above described and rigidly mounted on the lower platen 5 andprovided with heating means. Where such an article is to be a multiple celled article I provide a suitable number of suchcore members 11 for each article, three being shown in the drawings. These core members are for convenience made separately and mounted upon a bottom plate 12 designated to cooperate with the mold plates to form a completely closed cavity when assembled, the spaces 11 between the core members forming the partitions in the completed article. Each core member is providedwith a shank 11 which is held in a corresponding opening 12 in the bottom plate. In practice I heat the bottom plateand force the shanks 11 into the plate which shrinks thereabout, holding the cores permanently. Each core'is provided with steam cavities 11 and suitable connections to a steam line are provided by flexible or sliding steam connections.

I have .found that in practice the cores 11 require considerable force to draw them from the molded article and as the cylinder 1 and I ram 4 are single acting, in order to insure drawing of the cores, I provide a pair of extra hydraulic cylinders 13 mountedon thesides of the press head. These cylinders are double acting and to this end are provided with pistons 14 having piston rods 14 and 14? extending through packing glands 15 and 16 at the top and bottom of the cylinders respectively and provided with pistons 17 therebetween. The lower ends of rods 14 impinge against lugs 5 mounted on the sides of the lower platen 5 and thereby force the platen downward when hydraulic fluid pressure is admitted above the piston.

In order to provide means for ejecting the molds from the mold cavities 6 the ejector rods 10 previously mentioned are slideably guided in openings in the press head2 and are connected by a crossbeam 18. Rods 14 are'also connected by a crossbeam 19 above crossbeam 18 and normally spaced therefrom. Assuming that the mold is seated in the mold cavity 6 and the cores have been with drawn therefrom by action of piston rods.

14, further motion of. the pistons through rods 14 will cause crossbeam 19 to press crossbeam 18 downward and thereby the mold box or lining plates will be ejected.

In order to provide means for limiting the downward travel of the mold parts and to cll'ect resenting thereof in thecavity 6,

I provide a stop rod 20 passing vertically through openings in crossbeams 18 and 19 and provided with adjustable stops 21.and

22. By reversing the pressure in cylinders 13, thereby forcing rods 14 upward, crossbeam 19 will be raised and through stop rod 20 will raise ejector rods 10 and the supported mold parts.

Cylinders 13 are provided with pressure and exhaust ports and controlled bysuitable valves as is well'known in the art.

Having-described my invention, I will now describe the method of operation. The various mold parts are first heated to vulcanizing temperature and the ram 4 being at its llu lower position and the ejector rods 10 also I being at this lower position a cylinder of rubber compound, previously mixed and cut to the desired mass, and while warm, is placed on top of the cores 11. In order-to do this the front plate 9 is removed and replaced by hand. llydraulic pressure is then admitted to the lower ends ofv'cylinders 13 I thereby raising the mold boxes, and seatin them in the mold cavities 6 where the tapere walls act 'to-firmly press the mold box or lining parts together and also to retain them in said cavity. Hydraulic pressure is next admitted to cylinder 1 raising the ram' 4. and forcing the blank of rubber compound to flow throughout the mold cavity. The press is now in position to vulcanize the article which is accomplished by the-heat supplied to the various parts thereof. After vulcani- V zation the hydraulic. pressure is removed from I ram 4 and applied to the upper ends of cylinders 13. ods 14 exert downward pressure on the lower platen and attached cores therebypulling the cores partially from the article. The paneled wallsof the article interlocking with the mold and the fact that the mold plates are forced into a cavity having only a slight taper, as well as the pressure. of cylinders 13 u ward, prevent thearticle or molds being orced downward in this operation.

The cores are preferably slightly tapered so that as soon as they are moved slightly the atmosphere can enter the article. As soon as'tlie cores have been ejected a short distance the crossbeam 19 will impinge against the cross beam 18 whereby the mold will also be forced downwardly. The motion continues until the press is open and the top plate 7 will hang just inside the cavity 6 The front plate 9 is now removed by hand and the finished article may be lifted out without exerting force.

Having described my invention in such a manner as to enable anyone skilled in the art sure in either direction, rods extending through and actuated by said cylinders and impinging against the movable platen to pull said core, a cross bar connecting the opposite ends of said rods, an articulated mold designed to be seated in said mold cavity, and means associated with said cross bar for seating and ejecting said mold.

2. In a press for molding and vulcanizing rubber articles including stationary and movable opposed platens, a ram and cylinder for causing relativemotion and means for holding the cylinder and stationary ram in fixed relation; a pair of double-acting auxiliary cylinders. mounted on the stationary platen and provided with piston rods extending entirely therethrough, said rods impinging against the movable platen for the purpose of returning the movable platen, a cross bar connecting the upper ends ofsaid rods, a mold cavity supported by the stationary platen, an articulated molddesigned to fit said cavity and supported through the stationary platen by an ejecting mechanism. a core supported by the movable platen, and a lost motion device between said cross bar and said ejector whereby the platen and core may be separated from the mold and the mold subsequently cavity in one operation.

ejected from the mold 3. In a machine of the class described, ram mechanism, a platen on said ram, brackets on opposite sides of said platen, an upper press plage, vertical cylinders on opposite sides of sa1 ing therethrough and adapted to engage said brackets on said lower platen, and pistons on said piston rods, whereby steam introduced into said cylindersabove said pistons will move said piston rods downwardly against said brackets and force said ram mechanism downwardly.

4. In a machine of the class described, ram mechanism, a platen on said ram, brackets on opposite sides of said platen, an upper press plate, vertical cylinders on opposite sides of said upper press plate, piston rods extending therethrough and adapted to engage said brackets .on said lower platen, and

istons on said piston rods, whereby steam introduced into said cylinder above said pistons will move said piston rods downwardly upper press plate, piston rods extendagainst said brackets and force said ram mechanism downwardly.

5. In a machine of the class described, ram mechanism, a platen thereon, a container mold core secured on said platen, a shoulder around the lower end of said mold core, an upper press platen to o crate in opposition to said lower platen, a t rust rod extending downwardly throughsaid upperpress late. a mold-box secured on the lower end 0 said thrust rod and adapted to be engaged between said mold core shoulder and said upper platen, cylinders secured on opposite.

sides of said upper press platen, vertical piston rods in said cylinders, and mechanism connecting said piston rods and thrust rod whereby said thrust rod will be operated by said piston rods. I

6. In a machine of the class described, ram

mechanism, a platen thereon adapted to be raised and lowered by said ram, an upper press plate, a flask, having a mold receiving recess therein, secured to the under side of said upper platen, a mold-box adapted to enter said recess, a thrust rod secured to said mold-box and extending upwardly I through said upper platen, a container mold core, adapted'to enter said mold-box, secured on said lower platen, cylinders secured on opposite sides of said upper platen, piston rod mechanisms in said cylinders ada ted to force said lower platen downward y and lower said mold core .out of said mold-box, and means on the upper ends of said piston rods adapted to operate said thrust rods. downward to force said "mold-box downwardly out of said flask after said lower platen and mold core have reached thei lowermost position.

Intestimony whereof I affix my signature.

LOUISLW. HOTTEL. 

